The present invention relates to cement industry and, more specifically, to raw mixtures for the production of a cement clinker and is adapted to be used in low-temperature methods of production of a cement clinker.
Known in the art are raw mixtures for the production of a cement clinker which mixtures consist of lime, clay and ferrous components. In particular, a raw mixture is known consisting of the following components, percent by mass:
lime component (limestone)--79.54 PA1 argillaceous component (clay)--18.55 PA1 ferrous component (cinder)--1.91 PA1 lime component--55 to 63 PA1 argillaceous component--23 to 17 PA1 ferrous component--4 to 1 PA1 calcium chloride--17.8 to 4 PA1 potassium chloride--0.1 to 7.5 PA1 sodium chloride--0.1 to 7.5.
(cf. Yu.M.Boutt, V.V. Timashev "Practicum on Chemical Technology of Binding Materials", Moscow, "Vysshaja Shkola" (Higher School) Publishing House, 1973).
This raw mixture is typical for the raw mixtures employed in the production of a portland-cement clinker. A disadvantage of such raw mixtures in the production of cement resides in high temperatures of clinker calcination (1,400.degree. to 1,500.degree. C.) and a considerable specific fuel consumption.
Also known in the art are raw mixtures (cf. USSR Inventor's Certificate No. 275821 published July 3, 1970 in Bulletin No. 22; USSR Inventor's Certificate No. 326,152 published Jan. 19, 1972, Bulletin No. 4) containing lime and acidic (argillaceous and ferrous) components and calcium chloride in an amount of from 10 to 20% by mass. The ratio between limestone and acidic components is selected so as to obtain a raw mixture with the saturation coefficient (SC) of 0.9 with the account of CaCl.sub.2 and 0.7 without CaCl.sub.2.
The raw mixtures disclosed in the Inventor's Certificates referred to make it possible to lower the temperature of clinker calcination down to 900.degree.-1,200.degree. C., as well as to reduce the specific fuel consumption and to increase the grindability of clinker. However, in the production of a cement clinker the use of the raw mixtures referred to does not provide for utilization of alkali-containing raw materials and, in particular, alkali-containing dust recycle.